Oce 3121 Technical & Service Manual page 234

Image processor PBA
Image processor PCB
DC control PBA
DC controller PCB
Laser motor
Laser scanner motor
Laser scanner
Laser scanner
motor drive PBA
motor drive PCB
Laser unit
Laser unit
Laser driver PBA
Laser driver PCB
laser exposure
Generating the BD Signal
A laser ON signal (horizontal, synchronised signal) is needed when directing
a laser beam to the OPC. The laser beam detection signal (BD) is used to gen-
erate this start signal.
If two-sided copying or overlay copying is in progress, the edge of the copy
paper is detected. This determines any discrepancy with regard to the position
of the paper perpendicular to the transport direction
The result of this measurement varies the laser ON timing, in relation to the BD
signal. This ensures that the image will be at a specific position on every copy.
For details on how the side edge of copy paper is detected, see chapter 16, Du-
plex.
ed.1
6-facet mirror
6-facet mirror
Imaging
Imaging
lens
lens
BD mirror
BD mirror
BD PBA
BD PCB
Laser mirror
Laser mirror
OPC drum
Photosensitive drum
04 Exposure 511